🚀 go-pugleaf

jlange@radian.uucp (John Lange) writes:

>In nightclubs I have recently seen light effects which apparently
>use bright red, green, and blue lasers which are modulated with 
>mirrors (I think) to do interesting things like project color 
>images on a wall.  The red could be a simple He-Ne laser, but what 
>about the green and the blue?  I know these light sources can be 
>made with expensive 

Having many years of concert lighting experience, I can tell you that
it is unlikely that a night-club is using real lasers.  Several lighting
companies (notably Intellabeam) market devices that use incandescent
light with optics to SIMULATE laser beams.  They have a much wider
beam spread than a real laser and are usually used in confined
spaces only (like a nightclub).  Concerrts use real lasers, usually
ion lasers such as Argon.  HeNe is used to a small extent in concerts
also, but is generally shied away from.  The reason why nightclubs
USUALLY don't use real lasers is cost.  Argon (Green/Blue) can
run in the $10k-$20k range.  Plus, they usually require cooling
in the form of water (some newer ones are air-cooled, but,
that is relatively new to the entertainment world).  Also, REAL 
lasers are quite dangerous.  Most laser shows are inspected and
the operators licensed, because they can blind audience/crew members
if they hit the eye.  The average night-club doesn't want to get involved
in that area...  

I have seen some un-licensed HeNe shows (such as Peter Pan, which I
just worked on).  They used a .25mw HeNe to depict Tinkerbell.  That
power is supposedly legal in every state (according to what they told
me).  It is possible that the red is done with HeNe, but, if you
are seeing green or blue, most likely it is a simulator and the
red is also simulated.  If you happen to see WHITE, it is DEFINITELY
simulated.  WHITE lasers are QUITE expensive and VERY new.

And, yes, the beams are modulated (in both simulated and real) via
the use of mirrors (computer-controlled) and shutters.

--
Robert Garito
President, MicroLAN Technologies
rgarito@reef.cis.ufl.edu